For our highlander team, I'd like to say that it is probably very, very good Idea to use mic and communicate, a vent server could be set up if need, but I strongly advice you guys getting a mic.
If you don't like your voice/accent/slurring of your mouth. I don't care I'd like this highlander team, even though I myself are not in it, to be moderately successful in some sort of way, and good communication is always key.
Unless you've got some sort of telepathic communication with the rest of the team, I think the microphone is a thumbs up.
tl;dr Get a Mic.